A directional well casing retrieval process

Abstract

The present application relates to a kind of directional well sleeve process. Mainly solve the problem of bucking, cutting casing and difficult to make up in the sleeve milling process of the curved section of directional well, the sleeve milling string is characterized by comprising the following steps: analyzing well trajectory, dividing straight section, build-up section and the following part, determining sleeve damage location, calculating well curvature from build-up section to sleeve damage point;Section sleeve milling, first sleeve milling straight section, then sleeve milling directional section, sleeve milling to 20m above build-up section, replace sleeve milling string according to well curvature;Fish, take sleeve;Use lead seal adapter to make up and connect the lower broken casing;Sleeve milling string is pulled out;Cementing is carried out for the wellhead to the following 60m well section.The sleeve process of directional well can solve the problem of cutting casing by sleeve milling head and dispersing casing by sleeve milling cylinder bucking during sleeve milling, at the same time, new and old casing are made up by using special adapter, the problem of difficult to make up is solved, and the purpose of repairing severely damaged directional well is finally achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil field, in particular to a kind of directional well taking sleeve process. BACKGROUND

[0002] At present, the number of directional wells on oil field is increasing, after years of development, different degrees of casing damage occur in part of directional wells, and with the gradual deepening of development, the number of casing damage of directional wells will increase year by year. Because of the difference from the well trajectory of conventional straight well, the build-up section is easy to cut the casing, and even causes the loss of fish head, which leads to the damaged casing below the build-up section of many directional wells (groups) cannot be repaired, and the oil reservoir sand body and a large amount of remaining oil of the original directional well development cannot be developed and effectively utilized again. In order to adapt to the new needs of well repair market, the research on casing damage directional well taking and replacing casing repair technology is carried out.

[0003] For directional well taking sleeve construction, if the conventional straight well taking sleeve process is used, the following problems exist: ① Because the well trajectory of the build-up section of directional well is large, the large stiffness sleeve milling barrel has poor passing performance when milling, which is easy to cause the sleeve milling string to jump and break the casing; ② The sleeve milling head is in close contact with one side of the casing, which causes the casing to be cut and folded, and even causes the fish to be lost; ③ During the construction process, the sleeve milling barrel has a large contact area with the well wall, which is easy to cause the sleeve milling barrel to be stuck; ④ After sleeve milling, the ground stress is concentrated in the inclined open hole section, which is easy to collapse and bury the sleeve milling barrel in sand, and the annular area is large, which makes it difficult to return sand, easy to cause well leakage or sand sticking, and cause engineering accidents; ⑤ It is difficult to make up and connect, because the lower broken casing of the well section is not centered, there is an eccentric distance, which makes it difficult to introduce the lower broken casing when making up. SUMMARY

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the present application provides a kind of directional well taking sleeve process, which can solve the problem of sleeve milling head cutting casing and sleeve milling barrel jumping and breaking casing in the sleeve milling process, at the same time, using special make-up tool to make up new and old casing, solve the problem of difficult to make up and connect, finally achieve the purpose of repairing the serious casing damage of directional well.

[0005] The technical scheme of the present application is: a kind of directional well taking sleeve process, comprising the following steps:

[0006] (I), analyze the well trajectory, divide the straight well section, the build-up section and the part below, determine the casing damage position, calculate the well trajectory curvature from the build-up section to the casing damage point;

[0007] (II), section sleeve milling, first sleeve milling straight well section, then sleeve milling directional section, when sleeve milling to 20m above the build-up section, replace the sleeve milling string according to the well trajectory curvature;

[0008] (III), fish recovery, sleeve taking, 10-50m fishing at a time;

[0009] (4) using the lead seal adapter to repair the lower broken casing;

[0010] (5) pulling out the casing mill string;

[0011] (6) cementing the wellhead to the 60m well section below.

[0012] In the step (2), the casing mill string is selected according to the well curvature, when the inclination angle is in the range of 10.36°-52.82°, the string I is selected, and the build-up rate is in the range of 1.08°-12.19°; when the inclination angle is in the range of 10.84°-50.14°, the string II is selected, and the build-up rate is in the range of 1.02°-11.03°; when the inclination angle is in the range of 11.69°-41.42°, the string III is selected, and the build-up rate is in the range of 0.75°-6.09°.

[0013] The string I comprises a casing mill head, the casing mill head is sequentially connected with a centralizer, a variable-direction short joint A, a casing mill barrel and a variable-direction short joint B from top to bottom, and the variable-direction short joint B is sequentially connected with a plurality of casing mill barrels from top to bottom.

[0014] The string II comprises a casing mill head, the casing mill head is sequentially connected with a centralizer, a variable-direction short joint C and a casing mill barrel from top to bottom, the casing mill barrel is connected with another centralizer from top to bottom, and the centralizer is connected with a plurality of casing mill barrels from top to bottom.

[0015] The string III comprises a casing mill head, the casing mill head is sequentially connected with a casing mill barrel, a centralizer and a variable-direction short joint D from top to bottom, the variable-direction short joint D is connected with another casing mill barrel and centralizer from top to bottom, and the centralizer is sequentially connected with a plurality of casing mill barrels from top to bottom.

[0016] In the step (3), if the casing is always contained in the casing mill string and there is no cutting phenomenon, the casing is taken out 2m below the first casing collar after the casing mill directly passes the damaged point; if the casing has cutting phenomenon, the fish head is collected and pulled out by replacing the bell mouth casing mill head and cooperating with the original directional string.

[0017] In the step (3), if the casing has no cutting phenomenon, the fishing is carried out once every 30-50m; if the casing mill is seriously drilled, the fishing is carried out once every 10-30m after the eye is drawn and the eye is processed.

[0018] The casing mill head comprises a body, a centralizer sleeve is arranged at the top of the body, a centralizer block is arranged in the centralizer sleeve, and a ball is arranged between the centralizer block and the centralizer sleeve.

[0019] A plurality of longitudinal centralizer ribs are arranged in the centralizer block.

[0020] The present application has the following advantages: by adopting the above scheme, the casing mill pipe string is recombined by adopting the casing mill head and internal centralizing principle, the problem that the casing mill head cuts the casing and the casing mill cylinder jumps to scatter the casing during casing milling is solved; after the casing is damaged in the build-up section of the directional well and the following parts, the casing is taken out and completely repaired. According to the tool characteristics, the other drilling and jump phenomena generated during casing milling in the directional build-up section can be effectively reduced, and the casing taking construction success rate is further improved. According to the needs of the construction well, different structure process pipe strings are assembled, the wellbore curvature of 27.3° / 100m and the maximum casing milling angle of 15.6° of the directional well casing taking construction can be met. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the front view of the casing mill head in the present application;

[0022] Figure 2 is the left view of the casing mill head in the present application;

[0023] Figure 3 is the wellbore trajectory schematic diagram of example one;

[0024] Figure 4 is the wellbore trajectory schematic diagram of example two.

[0025] In the figure, 1 is the body, 2 is the screw, 3 is the ball, 4 is the O-ring, 5 is the centralizing sleeve, and 6 is the centralizing block. DETAILED DESCRIPTION

[0026] The present application will be further described below in combination with the drawings:

[0027] A casing taking process for directional wells, comprising the following steps:

[0028] (1) Analyzing the wellbore trajectory, dividing the straight well section, the build-up section and the following parts according to the well structure data, determining the casing damage position, calculating the wellbore curvature from the build-up section to the casing damage point, and preparing for the selection of the pipe string in the following sequence.

[0029] (2) Sectional casing milling, the straight well section is milled first, the conventional casing milling mode is adopted for the straight well section, the directional section is milled again, the pipe string drilling tool needs to be replaced, when the casing is milled to 20m above the build-up section, the casing milling pipe string is replaced according to the casing milling angle of the build-up section and the wellbore curvature, the positions and structures of the variable direction short circuit and the centralizer are adjusted, so that the casing milling pipe string and the casing reach a high matching degree, and the casing milling stability is further improved. When the inclination angle is in the range of 10.36°-52.82°, the pipe string I is selected, at this time, the build-up rate is in the range of 1.08°-12.19°; when the inclination angle is in the range of 10.84°-50.14°, the pipe string II is selected, at this time, the build-up rate is in the range of 1.02°-11.03°; when the inclination angle is in the range of 11.69°-41.42°, the pipe string III is selected, at this time, the build-up rate is in the range of 0.75°-6.09°.

[0030] The pipe column I includes a casing milling head, the upper end of the casing milling head is connected with a centralizer, a variable direction short connection A, a casing milling cylinder, a variable direction short connection B in sequence, the upper end of the variable direction short connection B is connected with a plurality of casing milling cylinders, wherein the angle of the variable direction short connection A is 1° or 1.5°, and the angle of the variable direction short connection B is 1.5°. The pipe column II includes a casing milling head, the upper end of the casing milling head is connected with a centralizer, a variable direction short connection C, a casing milling cylinder, the upper end of the casing milling cylinder is connected with another centralizer, and the upper end of the centralizer is connected with a plurality of casing milling cylinders, wherein the angle of the variable direction short connection C is 1° or 1.5°. The pipe column III includes a casing milling head, the upper end of the casing milling head is connected with a casing milling cylinder, a centralizer, a variable direction short connection D in sequence, the upper end of the variable direction short connection D is connected with another casing milling cylinder and centralizer, and the upper end of the centralizer is connected with a plurality of casing milling cylinders, wherein the angle of the variable direction short connection D is 1° or 1.5°.

[0031] The casing milling head includes a body 1, the upper end of the body 1 is provided with a centralizer sleeve 5, the inside of the centralizer sleeve 5 is provided with a centralizer block 6, an O-ring 4 is arranged between the centralizer block 6 and the centralizer sleeve 5 to ensure sealing and prevent fluid from entering to cause tool failure. Meanwhile, a bearing is arranged between the centralizer block 6 and the centralizer sleeve 5, the bearing ball 3 enables the centralizer block 6 to rotate, and the centralizer sleeve 5 is connected with a screw 2 to fix the ball bearing. Figure 1 Figure 2 The casing milling head adopts an existing shaft sleeve type centralizer sleeve milling head, uses a centralizing structure to improve the residence effect of the casing at the top of the rock breaking, prevents the cutter body from contacting the casing to cause cutting, relies on the shaft sleeve structure to reduce the friction between the casing milling head and the casing, and reduces the damage of the casing; the centralizer adopts a shaft sleeve type spiral centralizer, uses an outer centralizing structure to improve the centering effect of the casing milling cylinder in the wellbore, uses an inner centralizing block to improve the centering effect of the casing in the casing milling cylinder, uses the shaft sleeve structure to reduce the friction and damage of the casing caused by the bending contact between the casing and the casing milling cylinder, and further improves the compatibility between the casing, the casing milling cylinder and the wellbore. The casing milling cylinder adopts an existing product, and different diameters can be selected according to the well conditions.

[0032] The casing milling head adopts an existing shaft sleeve type centralizer sleeve milling head, uses a centralizing structure to improve the residence effect of the casing at the top of the rock breaking, prevents the cutter body from contacting the casing to cause cutting, relies on the shaft sleeve structure to reduce the friction between the casing milling head and the casing, and reduces the damage of the casing; the centralizer adopts a shaft sleeve type spiral centralizer, uses an outer centralizing structure to improve the centering effect of the casing milling cylinder in the wellbore, uses an inner centralizing block to improve the centering effect of the casing in the casing milling cylinder, uses the shaft sleeve structure to reduce the friction and damage of the casing caused by the bending contact between the casing and the casing milling cylinder, and further improves the compatibility between the casing, the casing milling cylinder and the wellbore. The casing milling cylinder adopts an existing product, and different diameters can be selected according to the well conditions.

[0033] The specific pipe column selection method is shown in the following table.

[0034]

[0035] ​(Three), fish, if the sleeve is always contained in the sleeve milling pipe column, and no cutting phenomenon, by direct sleeve milling through the sleeve loss point after the first sleeve coupling 2m, the implementation of the sleeve construction; if the sleeve has cutting phenomenon, then replace the horn mouth sleeve milling head with the original directional pipe column, implement fish head collection and introduction construction. Take the sleeve, according to the wellbore curvature and sleeve milling position angle, take the sleeve in time, 10-50m salvage once. If there is no cutting phenomenon of the sleeve, then 30-50m salvage once; if the sleeve milling is serious, up and down, the eye is processed, and the sleeve milling is still present, then 10-30m salvage once, in order to further reduce the contact stress of the sleeve in the sleeve milling cylinder and reduce the occurrence of sleeve milling.

[0036] (Four), sleeve butt joint, using lead seal repair device to repair the butt joint of the broken sleeve, and complete the complete repair of the sleeve joint part.

[0037] (Five), the sleeve milling cylinder pipe column is lifted out.

[0038] (Six), cementing is carried out on the wellhead to the following 60m well section, and then well completion is completed.

[0039] Example 1: North 2-360-Oblique P35

[0040] The well lost between 360.9-371.3m, the maximum well inclination in the well section is 11.7°, the build-up rate is 17.2° / 100m, according to the inclination data, the well trajectory is drawn. As shown in Figure 3 .

[0041] During construction, the well section above the build-up point is constructed by conventional sleeve milling, and when the sleeve milling reaches the well depth of 300m, the sleeve milling tool is replaced, and the main drilling tool structure is 290mm sleeve milling head+Φ219mm sleeve milling cylinder 1+Φ260mm ball centralizer+Φ219mm sleeve milling cylinder 1+Φ219mm hexagonal drill pipe. Sleeve milling to the well depth of 405m, (sleeve milling parameters: pump pressure 2MPa, displacement 1.7m 3 / min, drilling pressure 60kN, rotation speed 80r / min) The maximum inclination at this point is 14.2°.

[0042] The wellbore curvature changes greatly, and when the sleeve milling is replaced with a special drilling tool, the sleeve milling build-up well section is accompanied by different degrees of jump phenomenon. After sleeve milling for about 50m, the jump phenomenon gradually becomes obvious, but since the sleeve milling section is in the open hole state, the sleeve milling speed is fast, and the well construction is successfully completed.

[0043] Example 2: North 410-Oblique P47

[0044] North 410-Deviation P47 is a casing damage well, the casing damage depth is located in the interval of 157.56-158.56m, and the planned depth is 210m. In this well section, the maximum deviation angle is 11.8°, and the maximum build-up rate is 2.76° / 30m, as shown in Figure 4 .

[0045] In this casing taking construction, the casing mill is to 100m, then the casing taking string is replaced by the casing taking string for directional well, according to the wellbore parameters, it is known that the section of 100-210m is the build-up section, and the build-up rate is about 2° / 30m, and the maximum build-up rate is 2.76° / 30m. According to the wellbore build-up rate, the string structure III with the closest build-up characteristics is selected, and the build-up rate of the string structure is 2.35° / 30m, which is the closest to the build-up rate of the casing taking well section.

[0046] The well is subjected to casing taking and replacing overhaul construction, Φ290mm casing mill head + Φ219mm casing mill barrel + 194mm hexagonal square drill pipe are lowered, the casing mill is to 101m, the deviation is 6.6°, the test drilling tools are replaced: Φ300mm shaft casing mill head + Φ295mm spiral centralizer + Φ285mm variable direction short joint + Φ219mm casing mill barrel + hexagonal square drill pipe, the casing mill is to 209.5m below the casing damage point. The casing is lowered, the total length is 212.50m. The make-up is performed, the drilling pressure is 1kN, the manual make-up is 25 turns, the mechanical make-up is 20 turns, the pulling load is 400kN, the make-up is successful. The pressure test is performed: the water is used to positively press 15MPa, the pressure is stable for 30min, the pressure is not reduced, the pressure test is qualified, and the well is completed.

Claims

1. A directional well casing retrieval process characterized by It comprises the following steps: (1) analyzing the well trajectory, dividing the straight well section, the build-up section and the following part, determining the casing damage position, and calculating the well curvature from the build-up section to the casing damage point; (2) section casing milling, first casing milling the straight well section, then casing milling the directional section, and when the casing milling reaches 20m above the build-up section, the casing milling pipe string is replaced according to the well curvature; (3) fish recovery and casing taking, 10-50m fishing at a time; (4) using a lead seal adapter to connect the broken casing; (5) pulling out the casing milling string; (6) cementing the well section from the wellhead to the following 60m section. In the step (2), the casing milling pipe string is selected according to the well curvature, when the inclination angle is in the range of 10.36°-52.82°, the pipe string I is selected, and the build-up rate is in the range of 1.08°-12.19°; when the inclination angle is in the range of 10.84°-50.14°, the pipe string II is selected, and the build-up rate is in the range of 1.02°-11.03°; when the inclination angle is in the range of 11.69°-41.42°, the pipe string III is selected, and the build-up rate is in the range of 0.75°-6.09°. The pipe string I comprises a casing milling head, the upper end of the casing milling head is connected with a centralizer, a variable direction short joint A, a casing milling barrel and a variable direction short joint B in sequence, and the upper end of the variable direction short joint B is connected with a plurality of casing milling barrels in sequence. The pipe string II comprises a casing milling head, the upper end of the casing milling head is connected with a centralizer, a variable direction short joint C and a casing milling barrel in sequence, the upper end of the casing milling barrel is connected with another centralizer, and the upper end of the centralizer is connected with a plurality of casing milling barrels. The pipe string III comprises a casing milling head, the upper end of the casing milling head is connected with a casing milling barrel, a centralizer and a variable direction short joint D in sequence, the upper end of the variable direction short joint D is connected with another casing milling barrel and centralizer, and the upper end of the centralizer is connected with a plurality of casing milling barrels.

2. The directional well casing operation of claim 1, wherein: In the step (3), if the casing is always contained in the casing milling pipe string and there is no cutting phenomenon, the casing taking construction is implemented 2m below the first casing collar after the casing milling passes the casing damage point; if the casing has cutting phenomenon, the fish head recovery construction is implemented by replacing the bell mouth casing milling head and cooperating with the original directional pipe string.

3. The directional well casing landing process of claim 2, wherein: In the step (3), if the casing has no cutting phenomenon, 30-50m fishing is implemented at a time; if the casing milling is seriously drilled, 10-30m fishing is implemented at a time after up and down and eye opening treatment.

4. The directional well casing landing procedure of claim 3, wherein: The casing milling head comprises a body (1), the upper end of the body (1) is provided with a centralizer sleeve (5), the centralizer sleeve (5) is internally provided with a centralizer block (6), and the centralizer block (6) and the centralizer sleeve (5) are provided with a ball (3).

5. The directional well casing landing procedure of claim 4, wherein: The centralizer block (6) is internally provided with a plurality of longitudinal centralizer ribs.

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